Anti-slip tread



Mam}! 1958 L. K. NELSON 2,826,830

' ANTI-SLIP TREAD' Filed Feb. 10, 195

IN VEN TOR.

Leland K Nelson BY Whitehead, V09! 6 Lowe Pmj zf g ATTORNEYS United States Patent 9 This invention relates to anti-slipping means for shoes and boots, to the incorporation of anti-slipping elements into the solesand heels of shoes and boots and more particularly to a novel and improved anti-slip boot sandal of the class which may be detachably secured-t0 a shoe or boot.

A' primary object of the invention is to provide a novel and improved anti-slip element for incorporation into the heels and soles of shoes or boots as anti-slip means or for use as an anti-slip boot sandal which is especially adapted to adhere to exceedingly slippery wetrocks and rock-like surfaces which are covered with moss, lichens and similar growths. r

Other objects of the invention are to provide a novel and improved anti-slip boot sandal of such improved anti-slip element for adherence to wet, growth covered rocks and the like, which: (a) gives an individual secure footing when he is wading in a stream bed or similar channel; (b) includes both anti-slipping heel and toe portions for full foot protection; (0) incorporates in such sandal an improved heel and toe interconnection which permits a full freedom of boot movement the'sarne as if the sandals were not secured thereon; (d) does not rely upon calks for adherence to rocks but will adhere to wet slippery rocks at any point where the sandal contacts a rock surface; and (e) is simply constructed, and a low cost, neat appearing, rugged and durable unit.

With the foregoing and other objects in view, all of which more fully hereinafter appear, my invention comprises certain-novel and improved constructions, combinations and arrangements of parts and elements as hereinafter described, defined in the appended claims and illustrated in preferred embodiment in the accompanying drawing, in which:

Figure l is a side view of a boot with my improved anti-slip sandal secured thereon.

Figure 2 is a plan view of the sandal per se.

Figure 3 is a front view of the sandal.

Figure 4 is a rear view of the sandal.

Figure 5 is a front view of the sandal, similar to Fig. 2, but with the toe portion rotated with respect to the heel portion suggestive of the manner in which the toe of the boot will rotate with respect to its heel as a wearer places his toe on the side of a rock.

Figure 6 is a longitudinal sectional elevation view of a part of the heel portion as taken from the indicated line 66 at Fig. 2, but with the elements thereof modified to accommodate an undersized boot heel as illustrated;

Figure 7 is a fragmentary sectional'detail of the showing at Fig. 6 but on an enlarged scale.

Figure 8 is a side elevation view of a boot with antislip elements aihxed to the heel and sole to illustrate another embodiment incorporating the principles of my invention and with portions broken away to show parts otherwise hidden from view;

Figue 9 is a diagrammatic, greatly enlarged sectional view of a representation of a rock surface and the surface of anti-slip material gripping the rock surface.

7 Patented Mar. 18, 1958 A great deal of study has been made to develop shoes and boots which will not slip upon various normally slippery surfaces and there has been many types of antislip boot sandals and shoes for various purposes. Any analysis of the nature of different slippery surfaces would indicate that such surfaces could be classified in some manner according to their hardness and smoothness. It would be quickly recognized that a material which will not slip on one type of surface would be slippery on another surface. Also it would be recognized that the slipperiness of a given surface is changed radically when wetted by water or oil. For example, a boot sandal having hobnail calks will stick to a wooden surface but sharp spike calks are necessary for sticking to an ice surface. Where it is desired to walk over a dry rock surface as on the face of a mountain, metal calks are undesirable and rubber soles are the best. In one case, as with calks, adherence is attained by cutting into the slippery surface while in the other case there isfrictional adherence.

A real problem lies in the provision of a boot surface or boot sandal for wading in streams. Here, the difficulty lies in the fact that in many streams there are watersmoothed rock surfaces which are covered with growths of moss which give the rocks a slimey, smooth surface. Rubber soles, or any other type of boot sole which adheres to a surface by frictional adhesion are useless because of the moss slime, while hobnails and calks of metal which may cut through the moss and contact the rock surface cannot penetrate or hold onto the smooth surface. There is therefore, a real and definite need for a material which may be incorporated into a boot or sandal bottom surface or as a calk or the like which is especially adapted to provide gripping and adhesion on wet, smooth, mossslimed rock surfaces such as encountered in stream wading and like activities.

With such in view, the present invention was conceived and developed and comprises, in essence, the discovery that a soft, malleable, metallic substance can be adapted to adhere to smooth, moss-slimed rock surfaces, that such material can be incorporated in the development and construction of an improved anti-slip boot sandal and which takes advantage of such features of construction, all as hereinafter described in detail.

' The metallic adhering material must necessarily be hard enough to cut into and to crush growths on a rock surface but it was found that adherence could be attained only if the metal were soft and malleable and would permit the small irregularities of the rock surface to bite into the surface of the metal and the metal to conform to the rock surface. Such is illustrated at Fig. 9 where the small surface irregularities 10 of a rock 11 will bite into the undersurface of a metal sole piece 12 while the growths 13 which adhere to the rock are crushed between the irregularities of the rock. In addition to the need for a metal considerably softer than the rock surface it was found necessaryto have a metal which would not harden. A practical metal of such characteristic was unalloyed aluminum which is very soft and malleable or those soft alloys of aluminum which are commonly used as low strength structural forms and for similar purposes. The preferred metal was found to be bars of soft, hot-rolled or extruded aluminum alloy. Alloys which would work harden or form a work hardened skin could not be used. Even though such soft aluminum bars would adhere to wet rock surfaces the metallic surface skin which was formed on the aluminum bars when they were being shaped would tend to cause work hardening and eventually slipping.

Therefore, as a further step in the preparation of the metallic alloy,'the aluminum was treated or pickled in a bath of corrosive acid or base which would eat or dis solve the metallic surface skin to etch and expose a microcrystalline surface of the undisturbed metal underneath such surface skin. It was further discovered that this crystalline surface had a very fine textured, but definitely toothed roughness which seemed to remain as the alloy was Worn through use, as in wading, even when the aluminum was battered and worn away through contact with rocks. Although a precise explanation is not clear, it would appear that the effect of the acid was retained in the poresof the metal and it appeared that the pickling actioncontinued in some manner to tooth the metallic surfaces, pcrhaps by a continued dissolving action of the water or the likewhen the sandals are in use. It was discovered-that a sandal formed in the manner hereinafter described could be worn smooth and still retain its desirablegripping action, even to the point where the sandal was completely worn out.

Referring more particularly to Figs. 1 and 7 of the drawing, my improved sandal S comprises a heel plate 14 and a toe plate 15 which are joined together by a pair of transversely spaced, Sshaped links 16 set in orifices 17 at the confronting edges of the plates to provide a universal ,hinging action which compensates for misalignment of the elements and yieldably conforms with all movements of a boot B to which the sandal is attached, not only providing a transverse hinging action where the wearer of the boot stands on his toes, but also permitting the toe plate to twist longitudinally with respect to the heel plate as clearly illustrated at Fig. 5. Such improved, although simple hinging, permits the plates to yield in conformity to all movements of the boot and provides for sure footing at all times as where the wearer, places his toe upon a sloping rock surface which will twist and bend the boot and sandal in many different unpredictable ways.

The heel plate is formed of bar stock aluminum of sufficient width to cover the major portion of the heel undersurface and is shaped with an arched, upstanding backwall 18 couformably fitting the back curve of the boot heel, a transverse upturned offset 19 adapted to fit against the front of the heel and a forwardly extended arch segment 20 which extends underneath the arch of the boot towards the toe portion. A plurality of spaced knobs 21 depend from the underside of this heel plate. While such. knobs 21 are not essential for gripping and holding the place on a rock surface they provide projections which facilitate the cutting into moss and like underwater plants. When made of standard bar stock the heel plate 14 can be formed in dies in exceedingly simple operation. The backwall 18, upturn 19 and knobs 21 can all be formed in a single draw if desired.

It is contemplated that standard types of boots will have heels of standard width and that a boot heel will snugly fit into the space between the backwall 18 and the offset 19; however many boots are made with smaller heels and it is necessary to fit them into place, For this purpose, transversely spaced rows of orifices 22 are formed into the heel plate adjacent the forward olfset 19 and a small clip ,angle 23 having matching orifices is adapted to be set on the heel plate in a selected position upon the plate with such orifices in registration and there locked securely as by a screw 24, as clearly illustrated at Figs. 6 and 7.

The toe plate 15 is preferably formed of the same type and size aluminum bar stock as the heel plate to facilitate production procedure and the economical purchase and use of material. This bar is oriented transversely with respect to the axis of the unit with upturned side walls 25 at each end thereof to define the lateral confine within which the toe of a boot B rests. are also formed in this plate to depend from the under surface of the toe plate and the unit may be formed in a simple manner as by drawing in dies or the like.

The heel plate and toe plate are attached to a boot by any conventional strapping arrangement. A preferred arrangement is illustrated. The strap 26 is adapted to be extended about the back of a boot with the ends being extended over the front of the boot and joined together as by a buckle 27 at the heel plate. This strap is secured to each side of the backwall 18 as by a D ring 28 upstandingly attached to the backwall as by clips 29 The strap is passed through these D-rings 28, looped upon itself above the D-rings and stitched in place as at 30 as clearly illustrated at Figs. 1 and 2. t

A toe strap segment 31 is connected to each side wall 25 as in a D-ring 28 secured by a clip 29 to the wall 25. Each segment 31 is adapted to be passed over the top of a boot toe and connected to its mate by a buckle 27 as clearly illustrated at Figs. 1 and 2.

An alternate arrangement and modification of the invention is illustrated at Fig. 8 where a heel plate 32 and sole plate 33 is secured to the heel and toe of a boot B in any conventional manner, such, for example as by inset screws 34.

It is obvious that others skilled in the art can devise and construct alternate and equivalent constructions which are within the spirit and scope of my invention and it follows that my protection should be limited, not by the constructions illustrated and described but only by the proper scope of the appended claims.

I claim:

1. An anti-slip underface for boots and the like for use on rocks and like surfaces characterized by rock-like hardness and irregularity, comprising a metallic, etched-crystalline contact surface of malleable metal which is soft compared with said rock-like surfaces, and means for securing said under-face to a boot undersurface.

2. An anti-slip plate adapted to be attached to the undersurface of boots and the like for use on rocks and like surfaces characterized by rock-like hardness and irregularity, comprising a metallic plate of malleable metal, having an etched-crystalline surface, which is soft compared with said rock-like surfaces, and means for securing theplate to the undersurface of the boot.

3. An anti-slip plate adapted to be attached to the undersurface of boots and the like for use on rocks and like surfaces characterized by rock-like hardness and irregularity, comprising a soft malleable aluminum plate, having an etched-crystalline surface,,which is soft c0mpared with said rock-like surfaces and means for securing the plate to the undersurface of the boot.

ReferencesCited in the file of this patent UNITED STATES PATENTS 1,935,944 Dunn Nov. 21, 1933 2,595,694 Ogden May 6, 1952 2,678,507 Dye May 18, 1954 FOREIGN PATENTS 242,481 Great Britain Nov. '12, 1925 963,617 France July 17, 1950 1,024,617 France Apr. 3, 1953 A plurality of knobs 21 1 

